I've seen some japanese twitter discussion about [Hrududu Hrair]'s parts and how they parallel TR-6's standard parts so I tried to visualize some theories.
Some of these are obvious, like the [Hrair] nosecone-boost pod unit and [Woundwort] multi-connector boost pod or the weapon containers - which we still don't know how they differ besides the shape.
Likewise the high mega cannons are rather similar, main difference being TR-6's supporting struts. But again, we don't know enough about TR-S's version to compare them properly.
Another idea is the gigantic arm units compared to CBS. They're both composite weapons with all-range functions, TR-6 even uses them as sort-of giant arms in the [Hrairoo II] form.
Lastly the addon boosters - their functions are pretty similar, but there's a lot of differences in structure and fundamental approach, like TR-6's CBS addon boosters being built-in as a pair whereas TR-S works as two separate units.
The overall impression comes across as TR-6 taking cues from TR-S's approach - and of course both using mostly the same data as basis - leading to a somewhat more integrated and optimized designs.
Which fits the general vibe of them: TR-S is of course its own machine, but it still gives off the impression of being a [Hazel] on steroids, to the point a fair share of the gear are still fundamentally the same parts with upgrades attached. Meanwhile TR-6 is very much so a new thing, streamlining everything and involving more innovative and unusual solutions and approaches.